Slime control compositions containing organo-bromine compounds

ABSTRACT

The present invention relates to certain processes and compositions useful for inhibiting and/or controlling the growth of slime in water and, in particular, water employed for industrial purposes. Water employed in the manufacture of pulp paper and water employed in cooling water systems, as well as other industrial waters, provide environments which are conducive to slime formation. The novel compositions of the present invention are mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems. The slime, of course, is objectionable from an operational and/or an aesthetic point of view. Specifically, the invention is directed to and the use of compositions comprising a combination of 5-chloro-4-phenyl-1, 2dithiole-3-one and organo-bromine compounds (or mixtures thereof). The inventive compositions inhibit the growth of slime in water, or more specifically, possess biocidal activity against bacteria, fungi and/or algae. The organo-bromine compounds contemplated for use in accordance with the present invention may be exemplified by; bis-1, 4-bromoacetoxy-2-butyne; bis-1, 4bromoacetoxy-2-butene; alpha-bromo-p-methylacetophenone and betabromo-beta-nitrostyrene.

United States Patent 1191 Shema et a1.

[ SLIME CONTROL COMPOSITIONS CONTAINING ORGANO-BROMINE COMPOUNDS [75] Inventors: Bernard F. Shema, Glenside; Robert H. Brink, Jr., Doylestown; Paul Swered, Philadelphia, all of Pa.

[73] Assignee: Betz Laboratories, Inc., Trevose, Pa.

[22] Filed: July 12, 1971 [21] Appl. No.: 161,961

[52] US. Cl 71/67, 162/190, 424/277, 424/311, 424/331, 424/349 [51] Int. Cl A0ln 9/02 [58] Field of Search 71/67, 66; 424/277 [56] References Cited UNITED STATES PATENTS 2,931,754 4/1960 Baldridge 7l/l06 3,031,372 4/1962 Brack 424/277 3,629,465 12/1971 Manowitz et al. 71/67 3,639,293 1/1972 Shema 71/67 3,711,271 l/l973 Baker 71/67 Primary ExaminerJames 0. Thomas, Jr. Attorney, Agent, or Firm--Alexander D. Ricci; Eugene F. Miller 51 Oct. 1, 1974 [5 7 ABSTRACT The present invention relates to certain processes and compositions useful for inhibiting and/or controlling the growth of slime in water and, in particular, water employed for industrial purposes. Water employed in the manufacture of pulp paper and water employed in cooling water systems, as well as other industrial waters, provide environments which are conducive to slime formation. The novel compositions of the present invention are mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems. The slime, of course, is objectionable from an operational and/or an aesthetic point of view. Specifically, the invention is directed to and the use of compositions comprising a combination of 5-chloro-4-phenyl-1, 2-dithiole-3 -one and organobromine compounds (or mixtures thereof). The inventive compositions inhibit the growth of slime in water, or more specifically, possess biocidal activity against bacteria, fungi and/or algae. The organo-bromine compounds contemplated for use in accordance with the present invention may be exemplified by; bis-1, 4- bromoacetoxy-2-butyne; bis-1, 4-bromoacetoxy-2- butene; alpha-bromo-p-methyla.cetophenone and beta-bromo-beta-nitrostyrene.

10 Claims, No Drawings SLIME CONTROL COMPOSITIONS CONTAINING ORGANO-BROMINE COMPOUNDS BACKGROUND OF THE INVENTION The formation of slime by microorganisms is a prob- 5 lem which attends many systems. For example, lagoons, lakes, ponds, pools and such systems as cooling water systems and pulp and paper mill systems all possess conditions which are conducive to the growth and reproduction of slime-forming microorganisms. In both once-through and recirculating cooling systems, for example, which employ large quantities of water as a cooling medium, the formation of slime by microorganisms is an extensive and constant problem.

Airborne organisms are readily entrained in the water from cooling towers and find this warm medium an ideal environment for growth and multiplication. Aerobic and heliotropic organisms flourish on the tower proper while other organisms colonize and grow in such areas as the tower sump and the piping and passages of the cooling system. Such slime serves to deteriorate the tower structure in the case of wooden towers. In addition, the deposition of slime on metal surfaces promotes corrosion. Furthermore, slime carried through the cooling system plugs and fouls lines, valves, strainers, etc. and deposits on heat exchange surfaces. In the latter case, the impedance of heat transfer can greatly reduce the efficiency of the cooling system.

In pulp and paper mill systems, slime formed by microorganisms is also frequently and, in fact, commonly encountered. Fouling or plugging by slime also occurs in the case of pulp and paper mill systems. Of greater significance, the slime becomes entrained in the paper produced to cause breakouts on the paper machines with consequent work stoppages and the loss of production time or unsightly blemishes in the final product; this, of course, results in rejects and wasted output. The previously discussed problems have resulted in the extensive utilization of biocides in cooling water and pulp and paper mill systems. Materials which have enjoyed widespread use in such applications include chlorine, organo-mercurials, chlorinated phenols, organobromines, and various organo-sulfur compounds. All of these compounds are generally useful for this purpose but each is attended by a variety of impediments. For example, chlorination is limited both by its specific tox icity for slime-forming organisms at economic levels and by the ability of chlorine to react which results in the expenditure of the chlorine before its full biocidal function may be achieved. Other biocides are attended by high costs, odor problems and hazards in respect to storage, use or handling which limit their utility. To date, no one compound or type of compound has achieved a clearly established predominance in respect to the applications discussed. Likewise, lagoons, ponds, lakes and even pools, either used for pleasure purposes or used for industrial purposes for the disposal and storage of industrial wastes, become, during the warm weather, besieged by slime due to microorganism growth and reproduction. In the case of the recreational areas, the problem of infection, odor, etc. is obvious. In the case of industrial storage or disposal of industrial materials, the microorganisms cause additional problems which must be eliminated prior to the materials use or the waste is treated for disposal.

It is an object of the present invention to provide compositions for controlling slime-forming microorganisms in aqueous systems, such as cooling water systems and pulp and paper mill systems, and for controlling slime formation or microorganism populations in aqueous bodies in general. Moreover, another object of the invention is the provision of methods for preserving materials and for controlling slime-forming microorganisms in any aqueous system which is conducive to the growth and reproduction of microorganisms, and, in particular, cooling water and paper and pulp mill systems. These methods employ a combination of 5-chloro-4-phenyl-l, 2-dithiole-3-one and an organobromine compound (or mixtures thereof). The organobromine compound to be effective must possess the property of being biocidally active against bacteria, fungi and/or algae.

In the practice of the invention, the combination is added to the particular material to be preserved or to the system being treated, for example, cooling water systems, paper and pulp mill systems, pools, ponds, lagoons, lakes, etc., in a quantity adequate to control the slime-forming microorganisms which are contained by, or which may become entrained in, the system which is treated. It has been found that such compositions and methods control the growth and occurrence of such microorganisms as may populate these particular systems.

GENERAL DESCRIPTION OF THE INVENTION As earlier stated, the inventive compositions comprise a combination of 5chloro-4-phenyl-l, 2-dithiole- 3-one and a particular organo-bromine compound (or mixture thereof) with either compound being present in such a quantity as to impart a synergistic behavior for the purpose to the composition as a whole. Preferably, the compositions contain a percentage by weight ranging from about 5 to 95 percent of the dithiole- 3-one compound and from about 5 to about 95 percent of the organo-bromine compound. When these two ingredients are mixed either beforehand or by addition to the aqueous system individually, the resulting mixtures possess a high degree of slimicidal activity which could not have been predicted beforehand from the known activity of the individual ingredients comprising the mixture. Accordingly, it is therefore possible to produce a more effective slime-control agent than has previously been available. Because of the enhanced activity of the mixture, the total quantity of biocide required for an effective treatment may be reduced. In addition, the high degree of biocidal effectiveness which is provided by each of the ingredients may be exploited without use of the higher concentrations of each. This feature is not only important and advantageous from an economical point of view, but also most desirable from the pollution or ecological standpoints. Specifically, in this regard, it may be pointed out that the smaller the amount of a chemical that is required for effective treatment, the smaller the problem in treating the wastes from these systems. In both cooling water systems and in paper and pulp mill systems, certain discharge of waste water, e.g., blowdown in cooling water systems, is a necessity. However, because of the current concern and legislation regarding the discharge of wastes, the effiuent waste water must be treated to reduce and, hopefully, to eliminate any undesirable constituents. This treatment, of course, is time consuming and costly. Accordingly, a reduction in additive usage will result in a corresponding reduction in costs for the treatment of wastes containing these additives.

To demonstrate the synergism which is obtainable from the combination of the organo-bromine compounds with the 5-chloro-4-phenyl-l, 2-dithiole-3-one (supplied by Hercules Corporation under designation S-l6l2), various exemplary organo-bromine compounds were chosen. As earlier indicated, synergistic activity can be obtained by combining the dithiole- 3-one compound with any organo-bromine compound which exhibits growth inhibitory or biocidal activity with respect to bacteria, fungi and/or algae. The organo-bromine compounds which were chosen as representative are as follows: bis-l, 4-bromoacetoxy-2-butyne (Stauffer Chemical Co.: R-l7343 bis-l 4-bromoacetoxy-2-butene (Vineland Chemical Co.: V-l); alpha-bromo-pmethylacetophenone (Stauffer Chemical Co. N-3869) and beta-bromo-beta-nitrostyrene (Givaudan Corp.).

In order to illustrate the synergistic activity, the efficacy and the comparative effectiveness of the inventive compositions, various tests were utilized and will be described following SPECIFIC EMBODIMENTS EXAMPLE 1 SYNERGISTIC COMBINATION:

Compound A: -chloro-4-phenyl-l, 2-dithiole-3-one Compound B: bis-l, 4-bromoacetoxy-2-butyne The compositions of this Example contained 5-chloro-4-phenyl-l, 2 dithiole'3-one (referred to as Compound A in the Test Equations and in Tables I through IC) and bis-l, 4-bromoacetoxy-2-butyne (referred to as Compound B in The Test Equations and in Tables I through IC) in the weight ratios expressed in the Tables which follow. The compositions were tested for synergistic activity in accordance with the method described. The synergism test was utilized to evaluate each of the combinations of this Example and the following Examples.

Synergistic Index Test Synergistic activity was demonstrated by adding Compound A and Compound B in varying ratios and over a range of concentrations to liquid nutrient medium which was subsequently inoculated with a standard volume of suspension of the bacterium Aerobacter aerogenes. Following 2 days incubation, the lowest concentration of each ratio which prevented growth of the bacteria was taken as the end point. Growth or nogrowth was determined by turbidity or clarity, respectively, in the medium. End points for the various mixtures were then compared with end points for the pure active ingredients working alone in concomitantly prepared culture bottles. Synergism was determined by the method described by Kull et al (F. C. Kull, P. C. Eisman, H. D. Sylwestrowicz and R. L. Mayer, Applied Microbiology, 9, 538-41, (1961)) and the relationships,

TIC [CB/ (ICB/ G4) 0.4 OH

and, OIC/TIC 1.0 synergism where,

TIC Theoretical inhibition concentration for mixture IC Observed inhibition concentration for Compound A IC,, Observed inhibition concentration for Compound B Q Quantity of Compound A in the mixture, in g/g of mixture O Quantity of Compound B in the mixture, in g/g of mixture OIC Observed inhibition concentration for mixture For mixtures of Compounds A and B, and for Compound A and Compound B acting alone, the following results were observed:

TABLE I Weight Ratio End Point Data of A to B ppm A ppm B OIC TIC OIC/TIC BACTERICIDAL EFFECTIVENESS The bactericidal effctiveness of the mixture of Compound A and Compound B of this Example is demonstrated by the following Table in which the inhibiting power of a 50/50 by weight mixture of A and B is shown. Aerobacter aerogenes was employed as the test organism and a substrate technique was utilized. Specifically, the biocidal mixture was added in gradually increasing quantities to nutrient agar media which was then inoculated with A. aerogenes. The preparation was then incubated for 48 hours. The values set forth in the Table indicate the quantity of biocide required, in parts by weight for each 1 million parts by weight of the medium, in order to achieve complete inhibition of the growth of the test organism.

TABLE IA Quantity (ppm) required for inhibition Biocidal Material of A. aerogenes Compound A(5%), Compound 8(572), lnert(%) FUNGICIDAL EFFECTIVENESS centage kill (based on the initial count) may be calculated. In this evaluation the water sample was taken from a paper machine Saveall unit in the northeastern United States.

For the purposes of comparison, the mixture of A and B was evaluated together with two recognized commercial biocides, Pentachlorophenol and the Commercial Product described in Tablle I.

Quantity of Percent Kill Biocidal Material biocide (ppm) after 6 hours Compound A (5%). Compound B (5%) Inert (90%) 5 73 do. do. do. 10 69 do. do. do. 25 73 do. do. do. 50 97 do. do. do. I 97 Pentachlorophenol (I00 7r) i8 do. I0 81 do. 25 I00 do. 50 I00 do. I00 100 Commercial Product (22% active: Combination of Sulfone & cyanate biocides) 5 34 do. 52 do. 25 76 do. 50 70 do. 100 86 TABLE IB Quantitflgpm! for inhibition Biocidal Material P. expansum A. niger Compound A(571), Compound B(5% Inert(907r) SLIME CONTROL EFFECTIVENESS The inventive methods and compositions were also tested with respect to their performance in the control of slime formation in industrial systems. In this test an industrial recirculating water was obtained from a system which was currently experiencing problems in respect to the formation of slime by microorganisms. Such tests do not demonstrate the efficiency of the biocide employed with respect to specific species of microorganisms but instead supply a practical demonstration of the efficacy of the biocide tested in relation to those communities of microorganisms which have evidenced their ability to form slime in actual industrial systems.

In the testing of recirculating water samples, a substrate evaluation was employed. In such testing identical portions of water samples are treated with varying concentrations of biocide and two portions are left untreated to serve as controls. The control portions are plated for total count at the beginning of biocide treatment and all portions are plated for total count at some suitable time period(s) after beginning biocide treatment. Using the counts obtained from plating, the per- In the foregoing type evaluation, a percentage kill of approximately percent is considered to be most acceptable for industrial purposes. A perusal of the recorded percentages clearly establishes that the composition of the present invention, although less concentrated with respect to active ingredients as compared to the two commercial products, gave excellent rates of kill even at low treatment levels. As earlier expressed, excellent performance of a biocidal composition at low treatment levels not only provides a most desirable cost performance index, but also provides most desirable advantages from the aspects of pollution abatement, waste treatment costs and the preservation of the ecological strain.

EXAMPLE 2 SYNERGISTIC COMBINATION:

Compound A: 5-chloro-4-phenyl-l, 2-dithiole-3-one Compound B: Alpha-bromo-p-methylacetophenone The compositions of this Example contained 5-chloro-4-phenyl-l, 2-dithiole-3-one (referred to as Compound A in the Test Equations and in Tables 2 through 2C); and alpha-bromo-p-methylacetophenone (referred to as Compound B in the Test Equations and in Tables 2 through 2C). The compositions of this Example were tested in accordance with the test procedures outlined in Example 1. The data ascertained for the respective tests are recorded below under the commensurate Table.

Synergistic Index Test For mixtures of Compounds A and B, and for Compound A and Compound B acting alone, the following results were observed:

TABLE 2 Weight Ratio End Point Data of A to B ppm A ppm B OIC TIC OIC/TIC Initial Evaluation Biocidal Material TABLE 2-Continued Weight Ratio End Point Data of A to B ppm A ppm B OlC TIC OlC/TlC Secondary Evaluation BACTERICIDAL EFFECTIVENESS The bactericidal effectiveness of the combination of The composition was quite effective in controlling fungus growth when it is considered that it contained only 10 percent active material.

SLIME CONTROL EFFECTIVENESS 7 The test procedure used was that explained in Example 1. For comparative purposes, two commercial products were tested together with the composition of this Example. The results were:

TABLE 2C Quantity of Percent kill Biocidal Material biocide (ppm) after 6 hours Com- A Com- B (5%). Inert (9071) 5 77 pound pound do. do. do. do. do. do. do. do. It) 81 do. do. do. do. do. do. do. do. 25 85 do. do. do. do. do. do. do. do. 50 96 do. do. do. do. do. do. do. do. 100 98 Pentachlorophenol (10071) 5 48 do. 10 81 do. 100 do. 50 100 do. 100 100 Commercial Product (227: active-See Table 1C) 5 34 do. do. do. 10 52 do. do. do. 25 76 do. do. do. 50 70 do. do. do. 100 86 this Example was tested in accordance with the procedure outlined in Example 1. The values obtained are recorded in Table 2A which follows:

TABLE 2A Quantity (ppm) required for inhibition of A. aerogenes Compound A(57z Compound B(5/r), lnert (90%) FUNGlClDAL EFFECTIVENESS The effectiveness of the composition of Example 2 was tested in accordance with the procedures set forth in Example 1. The results were:

The results obtained with the lower percentage active compositions of the present invention were quite obviously impressive. The results were vastly superior to the Commercial Product which has found widespread acceptance and use. Moreover, the high activity of the low treatment level is extremely attractive from an economic viewpoint as well as from the aspect of the treatment of wastes containing the biocidal composition.

EXAMPLE 3 SYNERGISTlC COMBINATION:

Compound A: 5-chloro-4-phenyl-l, 2-dithiole-3-one Compound B: bis-1, 4-bromoacetoxy-2-butene The combinations of this Example contained 5-chloro-4-phenyl-l, 2-dithiole-3-one (hereafter referred to as Compound A); and bis-l 4-bromoacetoxy- 2-butene (referred to in this Example as Compound B). As with the previous Examples, combinations of these ingredients were tested in accordance with the various test procedures outlined in Example 1. The data obtained is recorded in the following Tables 3 through 3C.

synerglstic Index Test Again, the slime control effectiveness of the instant For mixtures of Compounds A and B, and for Comcomposition was much superior to the commercial pound A and Compound B acting alone, the following products at low treatment ranges and was significantly results were observed: better overall as compared to the 22 percent active TABLE 3 Weight Ratio End Point Data of A to B ppm A ppm B OlC TlC OlC/TIC The results obtained for this particular combination Commercial Product. I V established unequivocally that the two ingredients behave synergistically together.

EXAMPLE 4 BACTERICIDAL EFFECTIVENESS SYNERGISTIC COMBINATION:

This test procedure as described in Example 1 was Comp AI hl0r04phenylthi 6-3One utilized. The results established that the composition was effective in controlling this strain of bacteria. Compound B: Beta-bromo-beta-nitrostyrene a 7' TABLE 3A Quantity (ppm) required for inhibition Biocidal Material of A. aerogenes Compound A (S /1). Compound B (571). lnert (90%) 200 FUNGlClDAL EFFECTIVENESS Synergistic Index Test The fungicidal activity of the composition of this Ex- The synergistic activity of the combinations of ample was tested in accordance with the procedure 5-chloro-4-phenyl-l, 2-dithiole-3-one (referred to as previously described. The results were: Compound A) and beta-bromo-beta-nitrostyrene (re- TABLESB Quantity (ppm) for inhibition Biocidal Material P. expansum A. niger Compound A (5%), Compound B (5%). lnert (90%) l00 S00 1 CONTPOL EEEECTIVENES S ferred to in this Example as Compound B) was evalu- The Slime comm effectiveness of the present com ated in accordance with the test described. The results position was evaluated using actual paper mill water as were as follows: explained under the procedure outlined in Example 1. F r ixtures of Compounds A and B, and for Com- As with the previous Examples, the composition was pound A and Compound B acting alone, the following compared with commercially available products using r sults were observed:

this test.

TABLE 3C Quantity of Percent kill Biocidal Material biocidc(ppm) after 6 hours Com- A (5'71). Com- 8(571), lnert 5 67 pound pound do. do. do. do. do. do. do. It] 85 do. do. do. do. do. do. do. 25 98 do. do. do. do. do. do. do. 50 93 do. do. do. do. do. do. do. [00 96 Pentachlurophenol 10071) 5 48 do. 10 El do 25 100 do 50 I00 do. 100 100 Commercial Product (22% active See Table IC) 5 34 do. do. do. 10 52 do. do. do. 25 76 do. do. do. 50 70 do. do. do. 100 86 1 1 12 TABLE 4 The composition of this Example. as with the previous Examples, exhibited overall desirable and attracwcighl m End Point Dam tive slime control capacity. Of special interest is the of A w 8 ppm A ppm B OlC TlC OlC/TIC fact that low treatment levels of the composition were 5 capable of controlling the slime-forming organisms.

95/5 475 015 5,0 51 0.99 When the inventive compositions are employed in 50/50 2.0 2.0 4.0 5.83 69 the treatment of cooling or paper mill water, they are 23 Z 312, 2:8 & 0 73 preferably utilized in the form of relatively dilute solutions or dispersions. For example, a preferred solution 10 comprises between 5 to 65 percent by weight of the All of the combinations tested exhibited an OlC/TlC synergistic combination in admixture with various solof less than 1 which, of course, established that the invents and solubilizing agents. An example of such a dividual ingredients operated in concert to produce a synergistic biocidal product comprises from about 5 to synergistic result. 10 percent by weight of the bromo-nitrostyrene, from about 5 to 10 percent by weight of the 5-chloro-4- BACTERICIDAL EFFECTIVENESS phenyl-l, 2-dithiole-3-one and the remainder com- The efficacy of the compositions of this Example was posed of such materials as surfactants, stabilizers, or-

tested in accordance with the procedure outlined earganic solvents, such as alkanols, aromatic hydrocarlier. The results of the test clearly established that the bons, and/or water.

combination of the instant invention is effective even Surfactants such as the alkylaryl polyether alcohols,

at low percentages of active ingredients. polyether alcohols, sulfonates and sulfates, and the TABLE 4A- Quantity (ppm) required for inhibition Biocidal Material of Aaerugenes Compound A (5%). Compound B (571). Inert (907:)

FUNGICIDAL EFFECTIVENESS lilie, maybe employed to enhance the dispersibility and The fungicidal activity of the composition of this Exstability of these dispersions. The foregoing solutions of ample was tested in accordance with the procedure the biocidal compositions are utilized in order to insure previously described. The result of this evaluation was 35 the rapid and uniform dispersibility of the biocides as follows: within the industrial water which is treated. It has been TABLE 1T3 4 Quantity (ppm) for inhibition Biocidal Material P. expansum A. niger Compound A (5%), Compound B (5%). lnert (9092) 100 SUME CONTROL EFFECTIVENESS found that either aqueous or non-aqueous solvents are As in the previous Examples and in the manner set generally suitable in the preparation of compositions of forth in the previous Examples, the slime control effecthe invention, e.g., methyl cellosolve, organic solvents tiveness of the composition of the Example was tested. such as the aliphatic and aromatic hydrocarbons, e.g., The outcome of this evaluation and the data derived kerosene. Based upon the synergism study as outlined using the Commercial Products are set forth in the folabove, it was ascertained that in the treatment of palowing Table: per-mill and cooling water, effective biocidal action is TABLE 4Z3 Quantity of Percent kill Biocidal Material biocidc (ppm) after 6 hours C0m- A (5%), Comm5?! Inert 5 73 pound pound do. do. do. do. do. do. do. 10 84 do. do. do. do. do. do. do. 25 )l do. do. do. do. do. do. do. 50 97 do. do. do do. do. do. do. l00 98 Pentachlorophenol (l007z) 5 48 do. 10 81 do. 25 I00 do. 50 N do. 100 100 Commercial Product (22% active See Table 1C) 5 34 do. do. do. I0 52 do. do. do. 25 76 do. do. do. 50 70 do. do. do. 100 86 obtained when the concentration or treatment level of the combination or admixture of biocides is between 0.5 parts per million to 1000 parts per million, and preferably between I and 100 parts per million, based upon the total content of the aqueous system treated, such as the total quantity of cooling water or paper mill water.

The compositions may also be utilized for the preservation of slurries and emulsions containing carbohydrates, proteins, fats, oils, etc.; dosage levels for this purpose range in the vicinity of 0.5 to percent. The compositions of the invention which can be prepared by merely combining the respective ingredients and mixing thoroughly at standard conditions may be fed continuously to the treated system, e.g., by means of a metered pump, or may be fed periodically at predetermined intervals calculated to control the growth of slime-forming organisms in the system. Naturally, in the treatment of cooling water, the feeding of the inventive compositions must be designed to compensate for blowdown in those systems which employ that expedient.

Although the foregoing has been specifically directed to liquid formulations, the combinations of the invention may, of course, be formulated dry with well-known pelletizing agents, e.g., sodium chloride, talc, aluminate, etc. to produce solid pellets or briquettes which are added directly to the systems to be treated. The pellets or briquettes, of course, dissolve in accordance with predetermined conditions or rates.

In describing the inventive subject matter, the expression composition has been utilized. However, it is to be understood that physical compositions or combinations are not the sole utility of the invention. If, for example, the separate ingredients of the composition" are added independently to a particular system, it is intended that this usage of the subject matter is within the scope of the invention and is to be construed within the broad interpretation of composition and/or combination.

As would be expected, the inventive composition may be added to the cooling water or paper and pulp mill systems at any convenient point. Naturally, in once-through or non-circulating systems, the composition must be added upstream from the point or points at which microorganism control is desired. In circulating systems or pulp and paper systems, the compositions must be added at any point provided that the time lapse and the conditions experienced between point of addition and the point at which the effect of the composition is to be experienced are not so drastic as to result in the neutralization of the effect of the composition.

Although the invention has been described specifically as being directed to specific compositions comprising 5-chloro-4-phenyll, 2-dithiole-3-one in combination with the butyne as described in Example 1, the

acetophenone of Example 2, the butene of Example 3 or the styrene of Example 4, it is obvious that homologues, analogues, etc. of the dithiole-3-one compound certainly are operable for the purpose. Likewise, the derivatives of the specially exemplified organobromine compounds also have utility in the present inventive concept. Moreover, as earlier described, mixtures of the various organo-bromine compounds would also serve the purpose. The provision, of course, is that the organo-bromine compound possesses biocidal or growth inhibitory capacity with respect to bacteria, fungi, and algae.

It should be noted that while the evidence has been derived from the treatment of samples taken from paper and pulp mill aqueous systems, the compositions and methods of the present invention are broadly applicable to the treatment of aesthetic waters as well as in-- dustrial waters such as cooling; waters which are plagued by deposits formed by slime-forming organisms, or by the very presence of such organisms.

Having thus described the invention what is claimed 1. A method for controlling the growth of slimeforming microorganisms in an aqueous system which comprises adding to said system an effective amount of a combination comprising from about 5 to percent by weight of 5-chloro-4-phenyl-1,2-dithiole-3-one and from 5 to 95 percent weight of bromo-nitrostyrene.

2. A method according to claim ll wherein the combination contains approximately 50 percent by weight of each of said dithiole-3-one and said styrene.

3. A method according to claim 1 wherein the combination is added to said system in an amount of from about 0.5 to about 1000 parts by weight of said combination per parts by weight of said aqueous system.

4. A method according to claim 3 wherein the compound is beta-bromo-beta-nitrostyrene.

5. A method according to claim 3 wherein the combination is added to said system in an amount of l to parts per million parts of said aqueous system.

6. A method according to claim 3 wherein the aqueous system is the aqueous system of a cooling water system.

7. A method according to claim 3 wherein the system is the aqueous system of a pulp and paper mill system.

8. A slime control composition comprising from about 5 to 95 percent by weight of 5-chloro-4-phenyl- 1,2-dithiole-3-one and from 5 to 95 percent by weight of bromo-nitrostyrene.

9. A composition according to claim 8 wherein the composition contains approximately 50 percent by weight of each of said dithiole-3-one and said compound.

10. A composition according to claim 8 wherein the compound is beta-bromo-beta-nitrostyrene.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,839,008 Dated October 1, 1974 Inventor(s) Bernard F. Shema et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 4, the last line of Table I, both occurrences of "9. 0 should read 90. 0

In column 7, the next to last line of Table 2, 0. 72" should read 0.92

Signed and Scaled this sixteenth D a Of March I 9 76 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting ()jfit Commissioner ofPat'ents and Trademarks 

1. A METHOD FOR CONTROLLING THE GROWTH OF SLIME-FORMING MICROORGANISMS IN AN AQUEOUS SYSTEM WHICH COMPRISES ADDING TO SAID SYSTEM AN EFFECTIVE AMOUNT OF A COMBINATION COMPRISING FROM ABOUT 5 TO 95 PERCENT BY WEIGHT OF 5-CHLORO-4PHENYL-1,2-DITHIOLE-3-ONE AND FROM 5 TO 95 PERCENT WEIGHT OF BROMO-NITROSTYRENE.
 2. A method according to claim 1 wherein the combination contains approximately 50 percent by weight of each of said dithiole-3-one and said styrene.
 3. A method according to claim 1 wherein the combination is added to said system in an amount of from about 0.5 to about 1000 parts by weight of said combination per parts by weight of said aqueous system.
 4. A method according to claim 3 wherein the compound is beta-bromo-beta-nitrostyrene.
 5. A method according to claim 3 wherein the combination is added to said system in an amount of 1 to 100 parts per million parts of said aqueous system.
 6. A method according to claim 3 wherein the aqueous system is the aqueous system of a cooling water system.
 7. A method according to claim 3 wherein the system is the aqueous system of a pulp and paper mill system.
 8. A slime control composition comprising from about 5 to 95 percent by weight of 5-chloro-4-phenyl-1,2-dithiole-3-one and from 5 to 95 percent by weight of bromo-nitrostyrene.
 9. A composition according to claim 8 wherein the composition contains approximately 50 percent by weight of each of said dithiole-3-one and said compound.
 10. A composition according to claim 8 wherein the compound is beta-bromo-beta-nitrostyrene. 